Breaking Down Plastics with Bacteria


It is evident that plastics bring many societal benefits and offer future technological and medical advances. However, once plastic materials are created, they never go away! The disposal methods of plastic are diverse; yet, they cause accumulation of waste in landfills and natural habitats, physical problems for wildlife due to ingestion or entanglement in plastic, leaching of chemicals from plastic products, and transfer of chemicals to wildlife and humans.

According to researchers, eight million tons of plastic are dumped in oceans each year; this is a huge environmental threat that people are addressing in different ways. The plastic in trash may not degrade for 5,000 years. Synthesized into plastics are phthalates; compounds that make products bendable, but may adversely impact human reproductive development and health. As plastics slowly break down, these phthalates would leach into the surrounding environment.

In 2011, two high school students in Vancouver, Canada, Miranda Wang and Jeanny Yao, had a field trip to a waste treatment station. They were blown away by the enormous amount of waste in plastic that prompted them to try to find a solution to plastic pollution. Plastic is very hard to sort for recycling as all types have a similar density; Wang and Yao thought: “If we are making plastic synthetically, then we think the solution would be to break them down biochemically.”

Wang and Yao figured out that, if there were contaminated places along the local river, then maybe bacteria have evolved to degrade them. They collected samples from three sites, and enriched cultures with phthalates as the only food source. Finally, out of thousands of bacteria, they discovered a kind that could break down phthalates; several local species had indeed evolved to metabolize phthalates. They DNA-sequenced the bacteria, and found several ones that were not previously associated with phthalate degradation; that is a real discovery!

Most interestingly, Wang says: “We found that most efficient degraders came from the local landfill.” Nature was indeed evolving ways of dealing with the problem; one that we could someday use. Yao noted: “We were not the first ones to break down phthalates, but we were the first ones to look into our local river and find a possible solution to a local problem.”

It is worth mentioning that the two young scientists’ work earned the first place in the regional competition “The 2012 Sanofi BioGENEius Challenge Canada (SBCC)” in British Columbia, and a special award for their project with the greatest commercial potential at the contest’s finals.

Throughout their journey, Wang and Yao have also discovered their passion for science. They hope in the near future to be able to create model organisms that can break down, not only phthalates, but a wide variety of different contaminants.


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